The young people (18-20+) who go to Kos go there for partying. The bar street is full in the evenings but these people go home around 5-6AM so I doubt you will meet them on the streets the next day. That does not mean there aren't girls walking around. Me and my friend met a couple of German girls in their mid 20s when I was there. We only hanged out and went to the beach together, but that's another story.

In short, Kos town is small and there are many tourists so on the whole, it's ok for daygame. Expect to meet many of the same people while there though.

Ios not popular with Scandinavians anymore. Mostly Aussies, Canadians, Kiwis, some Americans, then other European countries.

To answer the question... yes it is good for day game. Some people go to Far Out during the day (5pm - 10pm) for the club scene, but there's plenty of people going to the various beaches on the island, chilling poolside, cliff jumping, etc. If you have Ios questions then shoot away, I've been the past few summers and don't plan on stopping any time soon.

Depends on the age range as well. Last year when I went to Ios it was overrun by ~17 yr old Scandi and ~22 yr old Aussie kids. If that demographic is too young for you you'll have to pick another island. Fortunately there are many to choose from: Santorini would be nice, Mykonos also, Paros isn't too shabby for a few days. Haven't been to Corphu or any of the others.